Re: [PATCH v7 10/25] ACPI / APEI: Tell firmware the estatus queue consumed the records

Borislav Petkov
2018-12-11T18:37:21Z

On Mon, Dec 03, 2018 at 06:05:58PM +0000, James Morse wrote:
> ACPI has a GHESv2 which is used on hardware reduced platforms to
> explicitly acknowledge that the memory for CPER records has been
> consumed. This lets an external agent know it can re-use this
> memory for something else.
>
> Previously notify_nmi and the estatus queue didn't do this as
> they were never used on hardware reduced platforms. Once we move
> notify_sea over to use the estatus queue, it may become necessary.
>
> Add the call. This is safe for use in NMI context as the
> read_ack_register is pre-mapped by ghes_new() before the
> ghes can be added to an RCU list, and then found by the
> notification handler.
>
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
> drivers/acpi/apei/ghes.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 366dbdd41ef3..15d94373ba72 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -926,6 +926,10 @@ static int _in_nmi_notify_one(struct ghes *ghes)
> __process_error(ghes);
> ghes_clear_estatus(ghes, buf_paddr);
>
> + if (is_hest_type_generic_v2(ghes) && ghes_ack_error(ghes->generic_v2))

Since ghes_ack_error() is always prepended with this check, you could
push it down into the function:

ghes_ack_error(ghes)
...

if (!is_hest_type_generic_v2(ghes))
return 0;

and simplify the two callsites :)

--
Regards/Gruss,
Boris.

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